Multiplex telegraphy.



No. 757,736. PATBNTED APR. 19, 1904.

J. J. GHEGAN.

MULTIPLEX TELEGRAPHY.

. APPLIGATION FILED JULY 3| 1902.

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x g x Al. M 8! S2 No. 757,736. PATENTED APR.19, 1904. J. J. GHEGAN. 5

MULTIPLEX TELEGRAPHY.

1 APPLICATION FILED JULY 3, 1902.

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No. 757,736. v I I PATBNTED APR. 19, 1904. J. J. GHEGAN. MULTIPLEX TELEGRAPHY.

APPLICATION FILED JULY 3, 1902.

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' UNITED STATES Patented April 19, 1904. I

PATENT OFFICE.

IVIULTIPLEX TELEGRAPHY.

SPECIFICATION forming part of Letters Patent N0. 757,736, dated April 19, 1904.

Application filed n; 3,1902. Serial No. 114,170,010 model.) 1

To all 1071,0177, it party concern:

Be it known that I, JOHN J GHEGAN, a citizen of the United States, and a resident of Newark, Essex county, New Jersey, have invented Improvements in Multiplex Telegraphy, of which the following is a specification.

This invention relates to telegraphic systems, and has for its object to increase the capacity of ordinary Morse telegraph-circuits for the way or intermediate as well as for terminal stations.

' I have devised a method whereby ordinary direct-current lines provided with ordinary Morse instruments, slightly modified, may be divided, so as to give two independent circuits at lntermediate as well as at terminal stations.

The means for accomplishing this are very simple, and consist of relay instruments actuated either by an alternating current or a vibrating current, which instruments are adapted to switch the opposite sides at all stations into and out of their main circuits in unison-that is, the instruments on one side'of a main line at all stations are switched into the main circuit in unison and at the same instant that the instruments on the other side at all the stations are switched out of the line. From this it will be seen that when any one of the keys at any station throughoutthe line is operated it will affect all the instruments on the same side at all stations and without having any effect upon the instruments on the other side. This system requires one circuit for the special relays; but this circuit may operate special relays for any number of separate lines that it may be desired to use.

As mentioned, the special controlling-relays may be actuated either by an 'alterating curarmature-tongues of the polar relays alte r nately shunt oi short-circiuit the neutral relays with their corresponding resistances, the signals being made by keys which normally keep the resistance of the rheos'tatsicut out, but when depressed let this resistance into the circuit, so that the armatures of the neutral relays do not respond to the weakened pulsations, but are held against their back stops, thereby closing the circuits. of their corresponding local Sounders. raise show in said patent an arrangement for takingofiithe static discharges from the line. Practice, however, has indicated theadvantage of several modifications on which I desire to secure further Letters Patent.

In my improved method I arrange each of the main polar relays with an extra pivoted tongue, which is operated mechanically'by the movements of the armature and which may be arranged in relation to the sides of the circuit, so that instead of shunting the sidesac' cording to which contact the armature touches (and both sides being in circuit while the rarmature is passing from one contact to the other) the sides are alternately switched out of the circuit and for an instantat the beginning of each pulsation both sides are in multiple in the circuit, I also find that the use of polar relays-for the sides of the divided circuit give better results than do the ordinary or neutral relays. I further find that better results are obtained by having these side polar relays wound differentially, the second winding being in an artificial line that is stat- Iifcally balanced tocounteract the discharges from the line proper; but this artificial line need 'not'be balancedwith the resistance of a the main line. I also find it of advantage to switch the artificial winding in and out in unison with the switching in and outof the main line through its winding. l In the accompanying drawings the three sheets taken together represent an arrange ment of lines and instruments illustrating an application of my improvements. j

Figure 1 is a diagram representing the gencrating-station; Fig. 2, an intermediate 'stao tion, and Fig. 3 a distant terminalstation.

However, I do not'limit myself to'the exact arrangement shown. nor to any specific combination of instruments beyond what is set forth in the appended claims.

In the drawings the regular polar relays are marked P; differentially-wound polar relays, DP; ordinary relays, Ry; rheostats, R; condensers, C; keys, K; sounders, S; inductioncoils, IC; retarding-coils, RC; main batteries, MB, and the alternating generator G. Each of the main polar relays is provided with a pivoted switching-tongue adapted to be mechanically operated by the relay-armature and by return-springs to alternately make contact with the said armature and with a contactstop. All'the main polar relaysP P P &c., are always in circuit with the generator G and are here shown as so connected up that with each like impulse sent from the generator through the circuitsay at each plus impulsethe armatures p 19 19 &c., make contact with the switching-tongues a a a &c., and with each impulse in the opposite direction the armatures p p 10 &c., leave the tongues a a a &c., which latter are then drawn into contact with the contact-stops b b If, &c.

The drawings show the instruments as in their positions when no messages are passing and at an instant when the current impulse from the generator G has drawn the armatures 10 19 &c., into contact with the switching-tongues a &c. For convenience and clearness 1 have arranged at each of the three stations represented by Figs. 1, 2, and 3 two sets of instruments X X X X, X X, operated by the alternating current, at the upper left-hand side of each figure, and two sets of instruments Y Y Y Y*, Y Y, operated by an additional direct current, at the upper righthand side of each figure, these latter sets Y, 620., being on a separate line, as shown.

It will be here noted that the local circuits of the various sounders throughout the system are shown open, which is the normal condition when no messages are passing, since the armatures of the relays for these sounders' are in such rapid vibration, due to the switching in and out, as hereinafter explained, that they do not contact with their stops long enough to close these local circuits.

At the generating-station I have shown four polar relays provided with switchingtongues-namely, a static governing polar relay SP, hereinafter referred to, a polar relay P for alternately switchingin and out the difierentially wound polar relays DP and DP of sets X X", a polar relay P for alternately switching in and out the relays Ry Rg/ of sets Y Y of instruments operated by an additional direct-current line, and a polar relay P to show that more additional lines could be operated, if desired.

Starting from the generator G, one side of which is to earth, as shown at E, the current is preferably divided at 1, one circuit passing through the coils of polar relays P P P SP and resistance R back to generator G. This arrangement of an independent circuit insures the steady responding of the polar relays at the generating-station; but it is not absolutely necessary. Returning to the dividing-point 1, the circuit of the alternating current continues on line 2 to switching-tongue a of the main polar relay P thence according to the position of armature p to one or the other of the set of instruments X X operated by the alternating current. The position of armature p shown continues the circuit through armature 19 line 3, and either through rheostat R or short circuiting through the key K to the coils of the differentially-wound polar relay DP, where it divides through the two windings, one winding leading to the alternating-current line-wire 4. and the other going through wire 5 to armature 10 of the static governing polar relay SP, which being in the position shown allows the circuit to continue through this armature p, tongue to, wire 6, and through condensers and resistances 1" C r C 1 0 and resistance R back to generator Gr.

It may here be noted that the keys K, &c.,

are arranged to open when depressed and normally being closed short-circuit the line out of resistances R R &c.

Returning to the main polar relay P it will be evident that when an opposite impulse from the generator G has moved the armature 10 away from the switching-tongue a and thusallo'wed the tongue to make contact with stop 5 the current from the generator G will be switched from the relay DP of set X and to the relay DP of set X through tonguea stop 6 wire 7 key K (or resistance R if key is opened,) and dividing through the windings of the differentially-wound relay DP will go through wire 8 to line-wire 4 and through wire 9 to contact-stop b of static polar relay SP and (as armature 10 has moved in unison with armature 10 that switched in relay DP through tongue a, wire 6, and condensers and resistances C C C, r r r, and R back to generator G.

From the foregoing it will be seen that the two sets X X of instruments K R DP S and K R DP S are alternately switched into circuit, and since the armatures of the main polar relays do not leave the switchingtongues until these tongues are stopped by their contact-stops that for an instant at the beginning of each alternate pulsation both sets X X of instruments are in multiple in the circuit. It will also be seen that as the polar relays SP and P act in unison the artificial line for statically balancing the discharges from the line proper is switched in and out of circuit with one of the diflerentially-Wound polar relays in unison with the switching in and out of the main line. The alternatingcurrent line-circuit 4 will now be traced to the next station, Fig. 2. This line is marked ACL at the upper right-hand side of Fig. l and is supposed to be continued by the line marked ACL at the upper left-hand side of Fig. 2. Proceeding online 10, Fig. 2, the circuit passes through the coils of the main polar-relays P and P to the switching-tongue a of the relay P, thence according to'the position of armature 19* to one or other of the sets X X of instruments in this intermediate station that are operated by the alternating current. The position of armature 39* shown continues the'circuit through the armature 10*, line 11, to dividing-point 12, whence part of the current goes through the coils of the differentially-wound polar'relay DP line 13, through key K when closed or rheostat B when the key is open, wire 14: t line-wire 15, and on to the next station. Returning to dividing-point 12, the other part of the circuit proceeds through line 16 to the primary coil of induction-coil IO',thence by line 17 to cut-off magnet CM and line 18 to line-wire 15.

The terminals of the secondary winding of the induction-coil IO are connected to the armature 0 and back stop d of the controllermagnet OM and also through the commutating-switch US with the second winding of the g The object the main line, which passes throughthe primary of ind notion-coil IO, .an impulse will be sent through the secondary of the coil IO and that by properly connecting the windings of coil 10. with the windings of thediflerentiallywound relay D1 respectively, as shown in Fig. 2, the induced current will pass through the relay DI in a direction opposite that of the static discharge. For instance, assuming that a current impulse has been sent through the line in a direction going from line 11 toward line 18, which for convenience I will call the forward direction, when this impulse is broken, the current induced in the secondary of induction-coil 1C being also forward will pass through the relay'DP in a direction from the switch CS to the relay DP and back to the secondary of 1C. On this break in the main current the static 'discharge'takes the opposite direction from the forward impulsethat is, this momentary discharge runs in a direction from line 13 to point 12. It will be evident that if the relay DP has one coil wound in a different direction from the other coil that the induced current through the second winding will counteract or neutralize the static discharge. As there are various manners of winding these relays, such as DP that is, as the relay may have its two coils wound either in opposite directions or side by side or one outside the other or end to endthe manner of connecting up the secondary of induction-coil IC with the relay DP will depend upon the special winding of the relaythat is, these connections must be so made as to cause the induced current to pass through the relay in a direction opposed to the direction of the static discharge.

to suit conditions. The controller-magnet GM is to prevent a discharge from the secondary of coil IO through relay DP on closing the circuit and to permit the discharge through relay DP on the interruption of the circiiit to counteract the effect of, the static discharge which occurs on each interruption. The controller-magnet CM' accomplishes this in the following manner: when no current is passing, the armature c is on its back stop d, thus short-circuiting the secondary Winding of the induction-coil IC and preventing the make. discharge from going to therelay DP However, the instantthat a current is passed through the line and controller-magnet CM the latter attracts its armature 0', drawing it away from its back stop (2, and thus opening the short circuit of the secondary winding of the induction-coil, so that when The switch CS is for the purpose of varying the strength of the coil discharge secondary of coil 1C must pass through relay DP and perform the oflice for which it was intended. On long lines of large static cato the discharge from the line.

Returning to the main polar relay 1, it will be evidentthat when an opposite impulse from generator G has moved the armature p I to DP of set X* through tongue 6;, contact- 1 stop Z2, and wire 19. The circuit through the X set of instruments. DP, K*, R*, 10 (1M and CS to line-wire 15 are the same as through the set X of instruments DP K R I0, CM, and CS. These two sets of instruments X X are alternately switched into and out of circuit by the relay P with each alternate pulsation from generator Gin unison with the alternate switching in and out of sets X X by relay P at the generating-station,

X and X being switched in and out togetherat ACL the circuit leads into the terminal station, Fig. 3, at AOL, thence by line 20 through the coils of the main polar relays P P and to the switching-tongue a". The position of the armature 19 determines which of the sets of instruments X X is switched into circuit in the same way. that the armatures of relays P and P determine the switching in and out of the sets of instruments X X X X. .The position of the armature 19 shown has switched in the set X in unison with the switching in of thesets X and X Anopposite impulse from generator G will switch in sets X X,'and X" in unison.

I have shown in the terminal station in place of the differentially-wound polar relays an ordinary relay Ry, adapted to close the local circuit of sounder S when open, and an ordinary polar relay P for the sounder.S. Relay Ry is connected to the armature of polar relay P by wire 21, and relay P is connected to contact-stop b" of relay P by wire 22. The lines from the sets of instruments X X are grounded at this terminal station at E 7 The instruments DP, DP DP", DP", Ry, and P are so adjusted that when a suitable resistancc, as R R 850., is thrown into the circuit their armatures fail'to respond to the pulsations thus weakened and are drawn against their back stops and close the local circuits of the sounders. These resistances R R", &c., are not sufficient to prevent the main polar relays from responding.

. The various circuits through which the alternating current may pass have now been described. As the alternating pulsations pass through the main polar relays and their ar matures and switching-tongues cause the alternating current to be switched first into the sets of instruments X X X and then into the other sets, X X X, at every connected station in the line the armatures of the instruments DP, DP DP, DP", P, and Ry normally vibrate to and from their back stops. These rapid vibrations do not allow the armatures to contact sulficiently with their stops to close the local circuits through the sounders'S to S; but if a key is opened, and thus a resistance thrown into the line on either side at any station on the line, all the relay-armatures on the same side will fall or be drawn against their back stops, where they will remain until the circuit is restored to its normal condition by closing the key to remove the resistance. It will be evident that the insertion of such resistance by a key on one side will not affect the instruments on the other side, as the set containing the inserted resistance is switched out of line when such other side is switched in.

I will now describe the method of connecting and operating additional lines with direct current, one of such lines being shown. This method consists in placing one of my modified polar relays in each station when it is desired to workone or both sides of divided lines. In the drawings these main polar relays are marked P, Fig. 1, P, Fig. 2, and P, Fig. 3. The magnets of these polar relays P P P are placed in the circuit of the first or alternating-current line, as already described, and the direct line conveying the current from the main batteries MB is connected to the switch ing-tongues a a 0f these relays. The regular relays and keys are connected to the respective polar-relay contactsthat is, the relay-Ry and key K are connected to the armature p of relay P by wire 23, and the relay Ry iand key K are connected-to the contact-stop b of switching-tongue a of polar relay P by wire 24 at the generating-station, Fig. 1. Following line-wire 25, DCL, Fig. 1, DCL, 26, Fig. 2, at the intermediate station, Fig. 2, the relay Ry and keyK are connected to the armature p of relay P by wire 27,

and the relay Ryf and key K are connected to contact-stop 72 by wire 28. Following the line-wire 29, DOL, Fig. 2, DCL, 30, Fig. 3, at the terminal station, Fig. 3, the relay R3 and key K are connected to the armature p of relay P by line 31, and the relay R z and key K are connected to the contact-stop b by line 32. The sets Y Y are connected to the ground at E, Fig. 1,and the sets Y Y are grounded at E, Fig. 3. It will now be evident that the movements of the armatures of polar relays P, P and P will cause the direct current to pass first through one set of instruments Y Y Y at every connected station on the line and then through the other sets Y Y Y in rapid succession, so that the armatures of relays Ry, Rg &c., normally vibrate between their front and back stops. These rapid vibrations do not allow the arma tures to contact sufficiently with their stops to close a local circuit through the sounders S to S but if a key is opened on either side all the relay-armatures on that side will fall or be drawn against their back stops and remain in that position until the circuit is restored to its normal condition byclosing the key. Hence it will be readily understood that by reversing the ordinary contacts of the key and relay, as shown, so that the former when pressed opens the main circuit and the latter when drawn or held against its back stop closes the local circuit of its sounder, the movements of the keys will be repeated on their corresponding sounders throughout the line. As the circuit changes from all instruments Y Y Y on one side to all instruments Y Y Q, on the other side, and vice versa, at each movement of the switching-tongues of the main polar relays, the key movements affeet only the instruments that are in circuit IOC IIC

at the corresponding periods with it. Gonsequently there is no interference between the action of the two sets of instruments.

1, In a telegraphic system, a main line, two

sets of transmitters and receivers at a plurality of stations, and means operated by the,mainline current for switching the corresponding sides of said sets alternately into and out of the main line.

2. In a telegraphic system, the combination of a main line, a circuit-changing relay operated by the main-line current, two sets of transmitters and receivers, and means actuated by said circuit-changing relay for connecting said sets alternately to said main line.

3. In a telegraphic system, the combination of a plurality of main lines connecting a plurality of stations, with a switching-relay and a duplicate set of transmitting and receiving instruments for each main line at each station the said relay adapted to switch the sides of the duplicate set of instruments alternately into and out of their main line, and all of said switching-relays adapted to be actuated by the current from one of said main lines, whereby all the corresponding sides of a line are connected or disconnected to it in unison.

4:. In a telegraphic system, the combination of a main line, a source of electricity adapted to send alternating-current impulses over said line, a polar relay through the windings of which the main line passes, and a pair of independent receiving-relays, with means actuated by said polar relay for switching said receiving-relays alternately into and out of said main line.

5. In a telegraphic system, the combination of a main line, two receiving differentiallywonnd relays, and means for switching one winding of each of said relays into and out of said main line alternately, with an artificial line, a relay adapted to switch said artificial line into the second winding of each of said relays alternately, said artificial line being statically balanced to counteract discharges from the main line.

6, In a telegraphic system, the combination of a main line, two receiving differentiallywound relays, and means for switching one winding of each ofsaid relays into and out of said main line alternately, with an artificial line statically balanced to counteract discharges from the main line, and a relay for switching said artificial line in and out of connection with the second winding of each of said relays alternately and in unison with the switching in and out of the main line through the first winding of said relays.

i 7 In a telegraphic system, a mainline. a *difi'erentiallywound relay adapted to have the current from the main line alternately switched into and out of one of its windings, and means for sending through the other winding of said relay a counteracting discharge while carrying along all the current in the main line.

8. In a telegraphic system, a main line, a difierentiallywound relay adapted to have the current from the main line alternately switched into and out of one of its windings, and means for sending through the other winding of said relay a current induced from the currentin the main line, while carrying along a all the current in said main line.

9. In a telegraphic system, a main line, an induction-coil having its primary winding in said main line, a differentially-wound relay having one winding inserted directly in and forming part of said main line and the other connected to the secondary winding of said induction-coil.

10. In atelegraphic system, a main line, an induction-coil having its primary winding connected to said main line, a differentiallywound relay having one winding connected to ,said main line, and means for shunting the secondary winding of said induction-coil into 'or out of the second winding of said relay.

11. In a telegraphic system, a main line, an induction coil having its primary winding connected to said main line, a diflerentiallywound relay having one winding connected to the main line and the other connected to the secondary winding of said induction-coil, and means for short-circuiting this secondary winding of said induction-coil out of said relay during the make of the main-line circuit through the relay.

12. In a telegraphic system, a main line, an induction-coil, a controller-magnet and a differentially-wound relay, the primary of said induction-coil, the controller-magnet and one winding of said relay being connected to said main line, the secondary winding of said induction-coil being connected to the secondwinding of said relay and to the contacts of said controllerunagnet. Y

13. In a telegraphic system, a main line, an induction-coil having its primary winding in said main line, a differentially-wound relay having one winding inserted directly in and forming part of said main line and the other connected to the secondary winding of said induction-coil, and means for varyingthe strength of the discharges from the secondary of the induction-coil, through said relay.

7 In testimony WhereofI have signed my name to this specification 1n the presence of two sub- I 0 scribing Witnesses.

JOHN J. GHEGAN Witnesses:

EDITH J. GRIsWoLn, MABE-LLE F. LAKE. 

